PSY402 Theories of Learning Chapter 4 (Cont.) Schedules of Reinforcement

 When and how often reinforcement occurs affects learning.  Two kinds of schedules: When = interval schedules How often = ratio schedules  Each kind of schedule can be either fixed or variable.

Interval Schedules  Fixed Interval (FI) – reinforcement is available regularly after a certain amount of time goes by. The behavior must still be performed. Scallop effect.  Variable Interval (VI) – the time that must go by before reward varies. Described as an average time

Ratio Schedules  Fixed Ratio (FR) – a specified number of behaviors must be completed before reward is given. Post-reinforcement pause  Variable Ratio (VR) – the number of behaviors needed to obtain reward is different each time. Described by an average

Differential Reinforcement  Reward is contingent on performing the behavior within a specified period of time. Example: due dates for class assignments  For interval schedules, reward is also contingent on behavior but the opportunity still exists after each interval ends.

DRH Schedules  Differential reinforcement can be made contingent on a high rate of responding.  May create a vicious circle: Danger that the animal will give up if the high rate cannot be maintained. If responding decreases, no reward will be obtained. Without reward, the behavior decreases.

DRL Schedules  Reinforcement is contingent on a low rate of responding. Animal is reinforced for withholding its behavior – not for showing it. If a period goes by without a response then the reward is given.